Masonry with vertical reinforced concrete strengthening

ABSTRACT

A masonry infill in a load bearing structure ( 18 ), comprises courses of hollow masonry units ( 1 ) arranged to define a cavity ( 3 ) extending therethrough filled with reinforced cementitious material e.g. reinforced concrete. A lower end of the concrete reinforcement ( 2 ) is secured to a load bearing support ( 16,  FIG.  3 ). A body ( 6 ) is secured to the load bearing structure and receives an upper end of the concrete reinforcement so as to permit longitudinal sliding movement of the reinforcement upper end in the body, whilst constraining movement of the concrete reinforcement in a direction transversely of the infill The lower end of the reinforcement ( 2 ) may be built into the support, or slidably received in a further body ( 5,  FIG.  3 ). Alternatively one or both ends of the reinforcement ( 2 ) may terminate in a bond beam. Brackets ( 9, 9   a ) may be embedded in the concrete in the cavity ( 3 ) to transfer shear forces between the adjacent blockwork and the concrete.

BACKGROUND

Current techniques for constructing larger buildings usually involve the use of a load bearing frame of steel or reinforced concrete, with attached cladding and/or masonry infills. In the case of masonry walls in such structures and elsewhere, it is necessary to provide additional strengthening where the area of the wall increases beyond certain limits. The strengthening is required to support the weight of the wall; to resist environmental loading such as wind forces, differences in air pressure and earthquakes; as well as to withstand other dynamic service loads such as crowd pressure, vehicle impact or explosions. The required strength for a given structure is governed not only by the laws of physics but also by local building regulations.

Traditionally where additional strength is needed, walls have been supported by cross walls, piers and areas of wall thickening. More recently windposts have been developed, which are used in most building walls (particularly interior walls), if their length exceeds 4 m. The purpose of the windpost is to stiffen or strengthen the walling, in circumstances of particular lateral stress from wind induced pressure differences, crowd or other design loads. A windpost generally consists of a steel column secured at its top and base to the building frame or another suitable load-bearing structure. This form of construction brings with it the following disadvantages:

1. An expansion joint is required on either side of the windpost, where it interfaces with the adjacent masonry. Filler material is inserted between the post and the masonry block faces to form the joint.

2. Frame ties typically at 225 mm centres must be provided between the masonry and the post on both sides.

3. Mastic will often be a specification requirement.

4. The windpost will require fire protection.

5. Loss of acoustic and thermal insulation.

6. The windpost typically requires four bolt fixings, two at the base and two at the soffit.

7. The windpost must be erected before the walling and so isolated access (e.g. scaffolding) is required for safe work practice particularly at height.

Our invention seeks to replace the windpost and to achieve increased strength and ductility within the wall panel.

SUMMARY OF THE INVENTION

According to the invention, there is provided a masonry infill in a load bearing structure, comprising hollow masonry units arranged to define a cavity extending through adjacent courses thereof, the cavity being filled with reinforced cementitious material, a lower end of the cementitious material reinforcement being secured to a load bearing support; a body being secured to the load bearing structure and receiving an upper end of the cementitious material reinforcement so as to permit longitudinal sliding movement of the reinforcement upper end in the body, whilst constraining movement of the reinforcement in a direction transversely of the infill.

The reinforced cementitious material strengthens the masonry infill against transverse loading/deflection and helps to secure the panel within the load bearing structure. The reinforced cementitious material (e.g. reinforced concrete) also helps to transmit transverse loads applied to the masonry to the load bearing structure above and the load bearing support below.

The load bearing support may be a foundation, or another part of the load bearing structure, for example a beam. The body may be secured to or within a beam which forms a part of the load bearing structure above or within the masonry infill.

On their exterior, the masonry course or courses containing the cementitious material are indistinguishable from the adjacent masonry. This can have aesthetic advantages. The reinforced cementitious material may be used instead of a wind post, without requiring expansion joints frame ties, mastic, fire protection, sound insulation or dedicated isolated access during construction.

The reinforcing material may comprise steel bar (e.g. “rebar”). The optimum or acceptable relative section areas of the concrete and steel and the positioning of the bars in the cavity may be calculated in accordance with standard engineering principles for beams and columns subjected to point and/or distributed loading, taking into account design service conditions such as anticipated impact and wind loading, etc. The reinforced cementitious material will key to the interiors of the hollow blocks and their presence can therefore be taken into account when determining the size and position of the steel bars. Allowance must be made for any reduction in compressive strength caused by the presence of any mortar joints in the masonry. The masonry is preferably laid in mortar or like bonding/bedding material. Solid masonry units may be used in regions of the masonry infill away from the cavity.

In similar manner to the upper end, the lower end of the cementitious material reinforcement may be received in a body secured to the load bearing support so as to permit longitudinal sliding movement of the reinforcement lower end in the body, whilst constraining movement of the reinforcement in a direction transversely of the infill. Alternatively the lower end of the cementitious material reinforcement may be built into the load bearing support, e.g. fixed in concrete forming the load bearing support.

The body may comprise a socket in which the end (upper or lower, as applicable) of the cementitious material reinforcement is received. Where the load bearing structure or load bearing support is formed from concrete, the socket may be formed in a metal body inserted (e.g. cast) into the load bearing structure/support. Where the load bearing structure or load bearing support is a metal (e.g. steel) frame, the socket may be formed in a cleat secured (e.g. bolted) to the frame.

The cementitious material reinforcement may be a sliding fit in the socket (e.g. there may be a total radial clearance of 1 mm or less for a rebar of 16 mm diameter). This allows relative longitudinal movement to take place between the cementitious material reinforcement and the socket, thereby accommodating differential expansion between the masonry infill and the load bearing structure. Suitable boots, seals or sealant may be applied to prevent the wet cementitious material from entering the socket as the reinforced cementitious material is cast. Under transverse loading of the masonry, the reinforcing bar ends engage the interior sides of the sockets and transfer the transverse loads to the load bearing structure. Under such loading, the bond beam and reinforcing bars will tend to bowso as to produce a reactive moment at the socket. Reaction forces from the sockets at the bar ends and the stiffness of the bond beam and surrounding masonry tend to restrain and prevent excessive lateral movement of the masonry.

The upper course or edge of the masonry infill may be secured to the load bearing structure by other means besides the attachment at the reinforcement. Fixings which are conventional in themselves, such as metal brackets and head restraints, can be used for this purpose. Mortar beds between courses may also be reinforced by means which are conventional as such, for example using metal wire or mesh.

Additionally or alternatively, reinforcements such as rebars or suitably shaped elongate metal brackets may be embedded in the cementitious material in the cavity, with one or both of their ends extending into the masonry bed joints. For example, such brackets or reinforcements may extend to one side, to both sides, or to either side alternately, of the cavity, in each course, in every other course, in every third course, etc, depending upon the degree of reinforcement demanded by the particular service conditions of the masonry infill concerned.

More than one reinforced cementitious material filled cavity as described above can be provided, thereby providing effective reinforcement of horizontally long masonry infills, or at free vertical edges of apertures formed in a masonry infill.

The cementitious material reinforcement may comprise shorter lengths secured together end-to-end or overlapped to provide effective longitudinal securement, so that the hollow masonry units do not have to be threaded over the entire length of the reinforcement as the infill is constructed. The first length of the cementitious material reinforcement is secured to the load bearing support, and further lengths are added upwardly as the infill is built up. The cavity can be filled with cementitious material to encase the reinforcement as each masonry course is laid; or after two or more courses have been laid; or after the entire infill is otherwise complete. It is preferred that the cementitious material is not allowed to fully cure between successive pours, to eliminate cold jointing and promote bonding into a unitary whole. Threaded connections can be used to secure the lengths of cementitious material reinforcement end-to-end, but generally the overlapping securing method is preferred.

The masonry infill may also comprise a reinforced cementitious material (e.g. concrete) casting extending parallel to a course of masonry units. For example the reinforced cementitious material casting may comprise a bond beam formed within a course of hollow masonry units. These units may have a U-shaped cross-sectional profile within which the reinforcement (e.g. rebars) is placed, and within which the cementitious material of the bond beam is contained whilst it cures and afterwards. One or both ends of the reinforcement for the casting may be secured to the load bearing structure. Bodies secured to the load bearing structure in a similar manner to those used to secure the upper end of the above-described cementitious material reinforcement, may be used to secure the or each end of the cementitious material casting to the load bearing structure.

One or more courses of masonry above and/or below the cementitious material of the bond beam may be tied into the cementitious material by reinforcements extending into the cementitious material and into mortar filled spaces in or between the units of masonry in these courses. For example, rebar or suitably shaped elongate metal brackets may be cast into the cementitious material so as to extend into the vertical mortar joints (perpends or “perps”) in the adjacent course or courses above and/or below. Where the cementitious material is cast in the gap between the limbs of a U-cross-sectioned block, selected U-shaped blocks may be provided with holes in their bases, allowing the rebar or elongate brackets to pass downwardly into perpends of the course below, as well as upwardly from between the limbs of the U into the course above. The rebar or brackets may be assembled from shorter lengths joined end-to-end as building of the infill progresses, in similar way to the advantageous form of cementitious material reinforcement described above. In this way, the rebars or brackets may extend through and tie several courses of masonry above and/or below to the cementitious material casting or bond beam. Where the rebars or brackets pass through these courses in regions away from perpends, they may be grouted or mortared into vertical holes running through the masonry units concerned. The elongate brackets may be generally L-shaped, having a horizontal support foot which rests against the blockwork course below and stabilses the bracket against an adjacent block before it is built into the masonry.

It has been found that the reinforced cementitious material filled cavity running through masonry courses and with reinforcement ends secured to a load bearing support and load bearing structure as previously described, and/or the reinforced cementitious material casting extending parallel to the course of masonry units and having upwardly and/or downwardly extending rebars or brackets, as described above, both serve to resist crack propagation when the masonry infill is subjected to transverse loading.

In a further independent aspect, the invention therefore provides a reinforced cementitious material casting extending parallel to a course of masonry units, in which one or more courses of masonry above and/or below the reinforced cementitious material casting are tied thereto by reinforcements extending into the cementitious material and into grout or mortar filled spaces in or between the units of masonry in these courses, the reinforcements being formed from separate lengths with ends overlapped, or joined end to end, for example joined by threaded connections.

The invention correspondingly provides a method of constructing a masonry infill in a load bearing structure, the method comprising the steps of:

laying hollow masonry units to define a cavity extending through adjacent courses of the masonry infill and filling the cavity with reinforced cementitious material,

wherein a lower end of the cementitious material reinforcement is secured to a load bearing support;

a body is secured to the load bearing structure; and

an upper end of the cementitious material reinforcement is longitudinally slidably received in the body in use; the body constraining movement of the reinforcement in a direction transversely of the infill.

Further features and advantages of the invention will be apparent from the following description of illustrative embodiments made with reference to the accompanying schematic drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a half-hollow block and modular rebar as may be used as components of an embodiment of the present invention;

FIG. 2 is a plan view of the block and modular rebar of FIG. 1;

FIG. 3 is a front view of the lower part of a masonry infill embodying the invention constructed using the components shown in FIG. 1;

FIG. 3 a corresponds to FIG. 3, but shows an alternative method for securing the modular reinforcement together;

FIG. 4 shows the complementary upper part of the masonry infill of FIG. 3;

FIGS. 5 and 6 correspond to FIGS. 1 and 2 but show an alternative hollow block as may be particularly advantageous in constructing the upper part of the infill as shown in FIG. 3;

FIG. 7 is a side view of a receptor cleat as may be used as a component of an embodiment of the present invention, a rebar lower end being shown received therein;

FIG. 8 is a side view of a modified receptor cleat for receiving a rebar upper end;

FIG. 9 shows a transfer rod or bracket as may be used as a further component of an embodiment of the present invention;

FIG. 10 shows a junction between a vertical concrete reinforcement embodying the present invention and a bond beam;

FIGS. 11 and 12 show further and alternative structural details of the bond beam of FIG. 10;

FIG. 13 shows an embodiment of the invention serving as reinforcement adjacent to an opening in a blockwork wall;

FIG. 14 shows alternative elongate metal brackets in use in a preferred embodiment of the invention;

FIG. 15 is a perspective view of an elongate metal bracket as used in FIG. 14, and

FIG. 16 shows the bracket of FIG. 15 used as a shear transfer member/rebar positioning bracket in a bond beam; parts of the blockwork being omitted to show reinforcement details.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

FIG. 1 depicts a front elevation of a half-hollow masonry unit in the form of a building block 1 through which modular reinforcement (rebar) 2 can be placed vertically in the hollow portion 3.

FIG. 2 is a plan view of the half-hollow block 1 shown in FIG. 1 with the vertical reinforcement 2 located centrally within the hollow 3 and the hollow backfilled with a cementitious mix, e.g. 40 N/mm² premixed concrete.

FIG. 3 illustrates a section of the bottom of a bonded masonry infill wall 50 embodying the invention. The wall is formed from the half-hollow blocks 1 described above and standard solid blocks 1 b bedded in mortar or similar material to form joints 1 a. A receptor cleat 5 is shown fixed to a floor or floor slab 16 forming a load bearing support. Alternatively the load bearing support may be a beam, for example part of a building frame. The lower end of a modular section of reinforcement 2 is placed into the receptor cleat. Alternatively this end may be cast directly into the load bearing support 16 where the latter is made from concrete, for example. The bottom four courses of blocks are then laid in the normal manner, with the half-hollow blocks 1 placed over the reinforcement, such that the hollow aligns vertically with the block below to form a continuous vertical cavity containing the reinforcement. The modular reinforcement 2 is shown with a threaded connector 4 screwed onto its threaded upper end. A threaded lower end of the next modular reinforcement (not shown) is screwed into the connector to provide a continuous and full strength connection. Transfer rods or L-shaped brackets 9 are located in every second bed joint, with the shorter leg protruding out into the cavity which is then backfilled with a cementitious mix such as concrete. Transfer rods or L-shaped brackets 9 are located in every second bed joint, with the shorter leg protruding down into the cavity which is then backfilled with the cementitious mix. Other spacings of brackets/transfer rods 9 may be used, as appropriate to the degree of reinforcement required. The brackets/transfer rods assist in transferring shear stress between the reinforced cementations material in the cavity 3 and the surrounding blockwork, e.g. under transverse loading of the wall.

The structure shown in FIG. 3 a is similar to that shown in FIG. 3, except that the sections of modular reinforcement, rather than being secured together with threaded connectors 4, are placed with their ends overlapping, preferably by tying the next section of reinforcement to the previous one before the resulting joint is encased in the blockwork being laid. Wire ties 2 a or other suitable means are used to secure the overlapped reinforcement ends together temporarily before they are encased in and permanently held together by the cured cementitious mix. The length of the overlap is made sufficient so that tensile stress in one section of reinforcement can be transmitted via shear stress at the interface to the surrounding cementitious matrix and then to the next section of reinforcement, without shear failure occurring between the matrix and the reinforcement ends (i.e. without the reinforcement ends pulling out of the cured cementitious mix). The length of overlap may be as specified in local building codes. For example 50× rebar diameter may be typical. This form of joining the modular reinforcement sections may be used in place of the threaded connectors 4 wherever those are mentioned in this document.

FIG. 4 illustrates a section of the top of a bonded masonry infill wall embodying the invention. A receptor cleat 6 (which may be substantially the same as the receptor cleat 5; although other arrangements are also possible, as further discussed below in conjunction with FIGS. 7 and 8) is shown fixed to the soffit 18 of a load bearing structure in which the masonry infill 50 is being constructed. The upper end of a modular section of reinforcement 2 is placed into the receptor cleat 6. The thread on the lower end 7 of this reinforcement section may be long enough to fully accommodate a connector 4 (not shown) so that this may then be screwed down onto the upper end of the modular reinforcement section below (not shown). A backing nut can be used if required, to form a rigid, play-free joint. Alternatively the uppermost connector 4 may be screwed up from the lower reinforcement section onto the adjacent uppermost reinforcement section. Yet alternatively, the overlapping joining method can be used for the sections of modular reinforcement, as described above with reference to FIG. 3 a. In that case, the upper end of the uppermost length of reinforcement 2 is poked into the receptor cleat 6 before the wire ties 2 a are secured. The top four courses of blocks are then laid in the normal manner, using half-hollow blocks 8 with no end wall, placed into position around the reinforcement so that the hollow aligns vertically with that of the block below. The threaded end 7 of the uppermost modular reinforcement section screws into the connector of the modular reinforcement below, or the two plain ends are overlapped (not shown in FIG. 5), to provide a continuous and full strength connection. Transfer rods or L-shaped brackets 9 are again located in every second bed joint, with the shorter leg protruding down into the cavity which is then backfilled with the cementitious mix. Throughout the height of the infill, other spacings of brackets/transfer rods 9 may be used, as appropriate to the degree of reinforcement required.

FIG. 5 depicts a plan view of the half-hollow block 8 with no end wall, with the vertical reinforcement 2 located centrally within the hollow 3 and the hollow backfilled with the cementitious mix.

FIG. 6 depicts an elevation of the half-hollow block 8 with no end wall which can be placed around the reinforcement 2 so that this extends vertically and substantially centrally in the hollow portion 3. The absence of the end wall ensures that this placement remains possible even when the corresponding reinforcement section 2 is secured at either end, between the cleat and the next lower reinforcement section.

FIG. 7 depicts an example of a receptor cleat 5 for locating the vertical reinforcement 2 in the desired position within the cavity at the base of the wall formed by the masonry infill The reinforcement is preferably located substantially in the centre of the cavity formed by the vertically aligned hollow parts of the hollow blocks 1. This particular example shows a receptor cleat 5 comprising a tubular socket 20 welded to a base plate 22 which can then be fixed to the floor slab or other load bearing support 16, using appropriate fasteners such as bolts, expansion bolts, etc. The reinforcement fits snugly in the tubular socket but this allows for longitudinal sliding to accommodate shrinkage etc.

FIG. 8 depicts an example of a modified receptor cleat 6 for locating the vertical reinforcement 2 at the desired location (e.g. substantially in the centre) in the vertical cavity at the head of the wall. This particular example shows a tube 24 welded to a base plate 20 which can then be bolted or otherwise fixed with appropriate fasteners to the soffit. The tube wall has a semi-cylindrical cut-away portion extending from its free end towards the base plate, over a substantial portion of its length. The reinforcement sits within the remaining semi-circular section 26 of the tube which gives it restraint against lateral loading at least in one direction, but allows sufficient access/tolerance to enable the modular reinforcement 2 to be connected to the modular section below as well as accommodate head deflections, shrinkage, expansion etc. The uppermost modular reinforcement section can therefore be fitted to the adjacent section without the need to screw the connector 4 up and then down or down and then up as described above.

FIG. 9 depicts a transfer rod or L-shaped bracket 9 which has a short leg 11 and a long leg 12 and a series of perforations 10 which, when built into a wall, allow the mortar/concrete etc to pass through, providing shear resistance. The bracket 9 may be used, as shown in and described with reference to FIGS. 3, 3 a and 4

FIG. 10 shows a portion of the masonry infill or wall 50 which accommodates both a reinforced concrete filled vertical cavity 3 and a course of hollowed out, U-shaped cross-section masonry units or blocks 30 for accommodating a bond beam 31. A pair of horizontally extending rebars 32 are suspended one above the other in the open channel foamed by the U-profile blocks 30 as this course is laid. The channel is filled with concrete or other cementitious material to form the bond beam and the next course can then be laid. L-shaped brackets or transfer rods 34 may extend from the horizontal channel into the perpends of the adjacent courses. These may be similar to the brackets 9 of FIG. 9. They assist in transferring shear stress or other forces/stresses between the reinforced concrete or other cementitous material in the horizontal channel and the surrounding blockwork. Holes may be provided in the bases of the U-profile blocks 30 where required, to allow the downwardly extending limbs of the downwardly directed brackets to pass into the perpends of the course below. Solid blocks 1 b may be used in regions of the wall away from the reinforced concrete filled vertical cavity 3 and the bond beam filled horizontal channel in the U-profile blocks 30.

As shown in FIG. 11, the ends of the rebars 32 are slidingly fitted into tubular sockets 36 welded to a base plate 40 of a further cleat 38. In this respect, the cleat 38 is similar to the cleat 5, and its base plate 40 may be fixed to an adjacent load bearing structure, e.g. the frame of a building, prior to fitment of the rebars and pouring of the bond beam concrete. In this way, one or both ends of the bond beam may be secured to the load bearing structure. Where the load bearing structure is formed from concrete, the body of the cleat may be cast into this structure. Brackets 34 may be provided, similar to the brackets 9 of FIG. 9.

FIG. 12 shows a modification of FIG. 11, in which the brackets 34 are replaced by L-shaped transfer rods 2 a, having threaded ends that may each be connected to one or more further modular rebar sections 2 in series, by threaded connectors 4. Alternatively, some or all of these joints may be formed by overlapping rebar ends, as described above with reference to FIG. 3 a. In this way, the bond beam may be tied to one or more adjacent masonry courses, both above and below. Vertical holes may be provided in the blockwork where the rebar sections and transfer rods 2, 2 a pass through away from perpends, and into which the rebar sections/transfer rods are grouted or mortared as the blockwork is built up. The lower transfer rods 2 a may have their ends bent over or partly bent over to form the final L-shape after placement of the corresponding U-profiled block 30, or the hole in the base of the block and/or the radius of the bend in the rod 2 a may be configured to allow the block to be threaded over the upper, free end of the rod 2 a as the block 30 is laid.

FIG. 13 is similar to FIG. 10, but shows the vertical cavity 3 filled with reinforced cementitious material e.g. concrete, used to strengthen the free vertical edge of blockwork adjacent to an opening 42, such as a window, door or service opening. Such edge strengthening may be required for higher transverse design loadings on the blockwork, for example loadings over 5 kPa. The vertical edge of the opening is formed by hollow half blocks 1 c which alternate course by course with the half hollow blocks 1, to provide the vertical cavity 3 extending through the courses adjacent to the opening 42. Rather than continuing upwardly as shown, e.g. to a soffit or other load bearing structure and securing cleat (not shown), the modular reinforcement 2 can terminate in the bond beam, where design loads allow. For example, L-shaped transfer rods 2 a such as shown in FIG. 12 can be used to terminate the vertically extending, modular reinforcement 2 in the bond beam. As another alternative, the bond beam may terminate in the course of blockwork above the opening 42 (e.g. at or slightly beyond the side of the cavity 3 opposite to the opening 42) to form a lintel above the opening 42. The lower end of the vertical edge reinforcement can similarly be terminated in a bond beam where appropriate, e.g. in the case of a window or service opening. Likewise the upper or lower part of the reinforcement 2 shown in FIG. 10 can terminate in the bond beam; or indeed both ends of such a vertical reinforcement can terminate in a bond beam.

FIG. 14 is similar to FIG. 4, but shows alternative elongate shear transfer brackets 9 a. These have a central portion embedded in the cementitious material in the vertical cavity 3, with opposed end parts extending into the blockwork on either side of the cavity 3. The vertical spacing of the brackets 9 a can again be varied, depending upon the degree of reinforcement required. The length of the bracket can similarly be varied.

However, to reduce the overall number of parts required in constructing a variety of reinforced blockwork walls, the bracket 9 a may be of a generally standardised form as shown on FIG. 15. As shown, it has a short foot part 44 extending at right angles to a main shank 46. It is provided with apertures 10 similar to those of the bracket 9, and for the same purpose. A notch 48 is cut into the shank extending from one edge across to the midline, to accommodate inter alia the modular reinforcement 2. A similar notch 52 is cut into the opposite edge of the shank, for a purpose explained below.

The standard bracket 9 a can also be used as a stress transfer member in a bond beam, as shown in FIG. 16. The foot 44 is used to support the bracket with the shank 46 propped vertically against an adjacent block 1 e, immediately before the bracket is built into the blockwork. When built in, the foot lies in a bed joint and the adjacent part of the shank lies in a perpend. (As used in FIG. 14, of course, the foot 44 lies in a perpend and the shank in a bed joint. The foot is not necessary in the arrangement shown in FIG. 14, but is preferred so as to keep the different kinds of brackets required to a minimum). The remainder of the shank 46 extends through an opening 54 in the base of the U-profiled block 30 a, so as to traverse the cavity in which the bond beam is to be formed. The distal end of the shank 46 projects upwardly beyond the top edges of the block 30 a a significant distance, so that it can be built into a perpend of the next course of blockwork immediately above the bond beam. In this way, the courses of blockwork above and below the bond beam are tied to the bond beam, with the brackets 9 a helping to transfer shear loads or other stresses between the bond beam and the surrounding blockwork. The notches 48 and 52 can be used to accommodate and support bond beam rebars 32 in the correct position within the bond beam cavity, before the bond beam concrete or other cementitious material is cast and cured. 

1. A masonry infill in a load bearing structure, the masonry infill comprising; a plurality of hollow masonry units arranged to define a cavity extending through adjacent courses of the masonry infill, the cavity being filled with a cementitious material; cementitious material reinforcement extending through the cavity and having a lower end which is secured to a load bearing support; a first body secured to the load bearing structure and receiving an upper end of the cementitious material reinforcement so as to permit longitudinal sliding movement of the upper end in the first body while constraining movement of the cementitious material reinforcement in a direction transversely of the masonry infill.
 2. A masonry infill as defined in claim 1, wherein the load bearing support comprises a foundation.
 3. A masonry infill as defined in claim 1, wherein the load bearing support comprises a part of the load bearing structure.
 4. A masonry infill as defined in claim 1, wherein the first body is secured to a beam which forms a part of the load bearing structure above the masonry infill.
 5. A masonry infill as defined in claim 1, wherein the lower end of the cementitious material reinforcement is received in a second body secured to the load bearing support so as to permit longitudinal sliding movement of the lower end in the second body whilst while constraining movement of the cementitious material reinforcement in a direction transversely of the masonry infill.
 6. A masonry infill as defined in claim 1, wherein the lower end of the cementitious material reinforcement is built into the load bearing support.
 7. A masonry infill as defined in claim 1, wherein the first body comprises a socket in which the upper end of the cementitious material reinforcement is received.
 8. A masonry infill as defined in claim 7, wherein the first body is inserted into the load bearing structure.
 9. A masonry infill as defined in claim 7, wherein the first body comprises a cleat.
 10. A masonry infill as defined in claim 7, wherein the cementitious material reinforcement is a sliding fit in the socket.
 11. A masonry infill as defined in claim 7, further comprising one from the group consisting of a boots, a seals or a sealant to prevent material from entering the socket as the cementitious material is cast.
 12. A masonry infill as defined in claim 1, further comprising means for securing an uppermost course of the masonry infill to the load bearing structure.
 13. A masonry infill as defined in claim 1, further comprising a reinforced cementitious material casting extending parallel to a course of the masonry units.
 14. A masonry infill as defined in claim 13, wherein the reinforced cementitious material casting comprises a bond beam formed within a course of hollow masonry units.
 15. A masonry infill as defined in claim 13, wherein the casting comprises a reinforcement having at least one end which is secured to the load bearing structure.
 16. A masonry infill as defined in claim 13, wherein one or more courses of masonry units vertically adjacent the casting are tied into the cementitious material by a number of tying reinforcements extending into the cementitious material and into mortar or grout filled spaces in or between the masonry units of the vertically adjacent courses.
 17. A masonry infill as defined in claim 16, wherein the tying reinforcements comprise lengths of the cementitious material reinforcement.
 18. A masonry infill in a load bearing structure the masonry infill comprising: a plurality of hollow masonry units arranged to define a cavity extending through adjacent courses thereof, the cavity being filled with a cementitious material; and a cementitious material reinforcement extending through the cavity and having an end which is secured to a bond beam formed within the masonry infill.
 19. A masonry infill as defined in claim 1, wherein the cementitious material reinforcement is comprised of steel.
 20. A masonry infill as defined in claim 1, wherein the masonry is units are laid in a bonding/bedding material.
 21. A masonry infill as defined in claim 1, further comprising a plurality of solid masonry units which are located in regions of the masonry infill spaced apart from the cavity.
 22. A masonry infill as defined in claim 1, further comprising a number of tying reinforcements embedded in the cementitious material in the cavity, each tying reinforcement comprising a projecting end extending into a masonry bed joint.
 23. A masonry infill as defined in claim 1, wherein the cementitious material reinforcement comprises a plurality of separate lengths co-operating to carry tensile loads.
 24. A masonry infill as defined in claim 23, wherein adjacent ends of the lengths are secured together by threaded connections.
 25. A masonry infill as defined in claim 23, wherein adjacent ends of the lengths are overlapped.
 26. A masonry infill as defined in claim 1, wherein the cavity runs adjacent to a vertically extending free edge of an opening formed in the masonry infill.
 27. A reinforced cementitious material casting extending parallel to a course of masonry units wherein one or more courses of masonry units vertically adjacent the cementitious material casting are tied thereto by reinforcements extending into the cementitious material and into grout or mortar filled spaces in or between the units of masonry in these courses, the reinforcements being formed from separate lengths with ends overlapped or joined end to end.
 28. A method of constructing a masonry infill in a load bearing structure, the method comprising the steps of: laying hollow masonry units to define a cavity extending through adjacent courses of the masonry infill; positioning a cementitious material reinforcement in the cavity; securing a lower end of the cementitious material reinforcement to a load bearing support; securing a body to the load bearing structure; and filling the cavity with a cementitious material; wherein an upper end of the cementitious material reinforcement is longitudinally slidably received in the body to constrain movement of the reinforcement in a direction transversely of the infill. 